Electronic display panel



Dec. 12, 1961 w. EJRUSSELL 3,013,182

ELECTRONIC DISPLAY PANEL Filed May 24, 1960 T1 13 T1 -21- TIEFE- INVENTOR Mu. MM .5 Pas $51.4

hwy dad ATTORNEYS United States Patent 3,013,182 ELECTRONIC DISPLAY PANEL William E. Russell, Boalsburg, Pa., assignor t0 HRB- Singer, Inc, State College, Pa., a corporation of Delaware Filed May 24, 1960, Ser. No. 31,474 Claims. (Cl. 315-169) This invention relates to electronic display panels and more particularly, to such panels which utilize an ionized gas to activate fluorescent phosphors.

In recent years it has become increasingly important in many applications to visually display information in two-dimensions. Computers, data analyzers, azimuth or position plotters, radar apparatus are only a few of the many electronic devices which have become dependent on rapid, accurate, visual display of information. Many types of electronic components have been utilized to accomplish this visual display. One such has been the gasglow electronic display panel.

Such gas-glow display panels comprise generally a transparent panel enclosure filled with an inert gas such as argon, helium or neon. Contained within the panel enclosure are two parallel planes of closely spaced electrodes. The electrodes of one plane are placed at right angles with respect to the electrodes of the other plane. By applying the proper potentials to an electrode of each plane, a glowing spot will appear at the intersection of the two electrodes due to the light producing properties of an inert gas when subjected to an electrical potential. Thus, by choosing different sets of electrodes, the device may be used visually to display information in two dimensions.

Such panels have not, however, found wide apprecia tion because of certain inherent disadvantages. These disadvantages are chiefly that the light intensity of the glowing spot is low, the spot is not sharply defined and is diffuse in appearance and the apparent size of the spot is large, tending to obscure accurate portrayal.

The electronic display panel of this invention seeks to overcome the inherent disadvantages of the prior, art devices bypproviding a display panel in which the glowing spot will be of greater light intensity and of more definite and well-defined proportions. This is accomplished by augmenting the light-producing properties of the gas by means of fluorescent phosphors.

The invention consists generally of a transparent panel enclosure filled with an inert gas. Two parallel sets of electrodes are located within the enclosure, the longitudinal axis of one set being perpendicular to the longitudinal axis of the other set. Fluorescent phosphors are placed between the two sets of electrodes so that the ultra-violet radiation resulting from the ionization of the inert gas when subjected to an electrical potential will fall upon the fluorescent phosphors and cause them to luminesce.

It is, accordingly, the principal object of this invention to provide an electronic display panel which overcomes the inherent disadvantages of the prior art.

Another object is to provide an electronic display panel in which the glowing spot Will be of greater light intensity and of more definite and well-defined proportions.

The above-rnentioned and other features and objects of this invention and the manner of attaining them will become more apparent and the invention itself will be best understood by reference to the following description of an embodiment of the invention taken in connection with the accompanying drawing, wherein:

FIG. 1 is a front view of the electronic display panel;

FIG. 2 is an enlarged perspective view of the electrode assembly;

FIG. 3 is a cross-sectional View of the electrode assembly taken along the line 3--3 of FIG. 2;

FIG. 4 is a schematic circuit diagram of a proposed use of the electronic display panel.

The novel electronic display panel is illustrated in FIG. 1. The front view accorded by that figure illustrates a transparent panel enclosure 10 containing two sets of electrodes, designated generally as 12 and 14.

' The transparent enclosure is filled with an inert gas such as argon. The two sets of electrodes 12 and 14 lie in closely adjacent parallel planes with the longitudinal axis of the electrode set 12 being perpendicular to the longitudinal axis of the electrode set 14. The electrode set 12 consists of a plurality of thin, closely-spaced wires suspended horizontally before the circular depressions of the constituent electrodes of the set 14. Circuit terminals such as 11 and 13 are provided for each of the constituent electrodes of both sets for connection to external circuitry.

The details of the electrode assembly can best be understood by reference to FIGURES 2 and 3. Referring first to the enlarged perspective view of FIG. 2, it is seen that the constituent electrodes of the set 14 are each composed of a rectangular metallic conducting plate 16 to which is bonded a non-conducting strip 18 with circular perforations 20. The perforations are cut to the full depth of the strip 18. Located within the perforations 20 and attached to the conducting plates 16 are scattered dots 22 of a fluorescent phosphor. The dots 22 almost completely cover the area of the perforation 20. Thin wires 24 and 26 forming the constituent electrodes of set 12 are horizontally suspended closely adjacent to the circular perforations 20.

The cross-sectional view of FIG. 3, taken along the line 3--3 of FIG. 2, illustrate in cross section the structural features just described. Like reference numerals are used to designate corresponding parts of the two figures. The rectangular conducting plate 16 has bonded to it the perforated strip 18. The strip 18 is perforated to its full depth and located within the perforation and attached to the plate 16 are the scattered dots 22 of'a fluorescent phosphor. The thin wire electrodes 24 and 26 of the set 12 are suspended horizontally before the circular depressions 20. t I

The operation of the display panel is accomplished in the following manner. When a potential difference of suflicient strength exists between an electrode of each set, as for example, the electrode 16 of the set 14 and the electrode 24 of the set 12, the argon gas contained between the two electrodes will be ionized. The polarity of the applied ionizing voltage is chosen such that the glow of the ionized gas is concentrated about the electrode 16 rather than the electrode 24. The radiation emitted by the glowing ionized gas is composed approximately of 40% visible light and 60% of invisible ultraviolet energy of 3900 A. (Angstrom units) wavelength. The circular depression 20 containing the fluorescent phosphor dots 22 will thus be bathed in this irradiated energy. The ultra-violet energy will cause the phosphor dots 22 to fluoresce brightly and define sharply the circular perforation. The strip 18 serves to shield the nearby perforations from the radiation occurring at the selected perforation.

Numerous modifications to the basic panel structure are possible. The phosphors may be selected to produce any desired color under fluorescence or selected electrodes may be given a different color to indicate a particular state of information. Other gases or mixtures of gases may be substituted in the system, although all inert gases are not suitable. For example, a mixture of argon and mercury vapor would produce ultra-violet energy of a shorter wavelength, but neon gas may not be used. Resolution of the panel may be improved by making the circular perforations of a smaller size. Of course, configurations other than circular may be used.

It can now be readily understood why the present invention provides an electronic display panel which achieves a glowing spot of greater light intensity and of more definite and well-defined proportions. In the priorart devices it was merely the visible light resulting from the ionization of the gas that defined the glowing spot. This spot has an ill-defined contour. In the present invention the previously unused ultra-violet energy accompanying the ionization is used to activate fluorescent phosphors which lie in a sharply defined circular pattern and thus augment and define the glowing spot. The result is a much improved electronic display panel.

A proposed use of the electronic display panel of the present invention is shown in the schematic circuit diagram of FIG. 4. The display panel 30 has connected to its vertically-arranged electrodes a horizontal scanning circuit designated generally as 32. Similarly the horizontally-arranged electrodes have connected to them a vertical scanning circuit 34. The horizontal scanning circuit 32 consists generally of a beam switching tube 36 to each of whose plates a vertically arranged electrode is connected. A sine wave horizontal scanning Signal is applied to the terminal 38 and is transformer coupled to each of the grids of the tube 36. All even-numbered grids are connected to one side of the signal and all oddnumbered grids to the other side. In this manner the scanning signal switches the beam of the tube 36 to the next vertical electrode every half cycle. Contrast for the display panel is achieved by applying a contrast Signal to the terminal 40, thence through the cathode-follower-connected triode 42 to the cathode of the tube 36.

The vertical scanning circuit 34 is similarly composed and consists of a beam switching tube 44 to whose grids is 'fed a transformer-coupled sine wave scanning signal applied at the terminal 46. The horizontally-arranged electrodes of the display panel 30 are applied to the plates of the tube 44 and the scanning signal switches from one electrode to the other each half cycle.

Another use of the panel is to utilize motor-driven rotary switches to achieve horizontal and vertical scanning. Contrast for the panel is provided in this case by including in the horizontal scanning voltage supply a simple voltage amplifier driven by a contrast signal.

While the foregoing description sets forth the principles of the invention in connection with specific apparatus, it is to be understood that this description is made only by way of example and not as a limitation of the scope of the invention as set forth in the objects thereof and in the accompanying claims.

What is claimed is:

1. An electronic display panel comprising a transparent panel enclosure containing an inert gas, a first set of elongated electrodes located within said enclosure, a second set of elongated electrodes located within said enclosure, said first set of electrodes lying in a plane substantially parallel to the plane of said second set of electrodes, the longitudinal axis of said first set of electrodes being substantially perpendicular to the longitudinal axis of said second set of electrodes and fluorescent phosphors located between said first and said second sets of electrodes.

2. An electronic display panel according to claim 1 wherein said first set of electrodes consists of a plurality of wire conductors and said second set of electrodes consists of a plurality of rectangular electrical conducting plates, and means connected to both said first and said second sets of electrodes for applying thereto an electrical potential.

3. An electronic display panel as set forth in claim 1 wherein said first set of electrodes consists of a plurality of wire conductors, said second set of electrodes consists of a plurality of rectangular electrical conducting plates and wherein said fluorescent phosphors are attached to said second set of electrodes.

4. An electronic display panel as set forth in claim 1 wherein said first set of electrodes consists of a plurality of wire conductors, said second set of electrodes consists of a plurality of rectangular electrical conducting plates, a perforated nonconducting strip bonded to each of said plates and said fluorescent phosphors being attached to said conducting plates in the perforated areas.

5. An electronic display panel as set forth in claim 1, and further comprising means connected to said first set of electrodes for selectively energizing the constituent electrodes in sequence, and means connected to said second set of electrodes for selectively energizing the constituent electrodes in sequence.

References Cited in the file of this patent UNITED STATES PATENTS 2,500,929 Chilowsky Mar. 21, 1950 2,877,376 Orthuber Mar. 10, 1959 2,926,286 Skellett Feb. 23, 1960 FOREIGN PATENTS 208,905 Australia July 1, 1957 

